You are given a binary string $$$s$$$ of length $$$n$$$. We define a maximal substring as a substring that cannot be extended while keeping all elements equal. For example, in the string $$$11000111$$$ there are three maximal substrings: $$$11$$$, $$$000$$$ and $$$111$$$.
In one operation, you can select two maximal adjacent substrings. Since they are maximal and adjacent, it's easy to see their elements must have different values. Let $$$a$$$ be the length of the sequence of ones and $$$b$$$ be the length of the sequence of zeros. Then do the following:
As an example, for $$$1110000$$$ we make it $$$0000000$$$, for $$$0011$$$ we make it $$$1111$$$. We call a string being good if it can be turned into $$$1111...1111$$$ using the aforementioned operation any number of times (possibly, zero). Find the number of good substrings among all $$$\frac{n(n+1)}{2}$$$ non-empty substrings of $$$s$$$.
Each test consists of multiple test cases. The first line contains a single integer $$$t$$$ ($$$1 \leq t \leq 10^5$$$) — the number of test cases. The description of test cases follows.
The first line of each test case contains $$$n$$$ ($$$1 \le n \le 2 \cdot 10^5$$$) — the length of the string $$$s$$$.
The second line of each test case contains the binary string $$$s$$$ of length $$$n$$$.
It is guaranteed that sum of $$$n$$$ across all test cases doesn't exceed $$$2 \cdot 10^5$$$.
For each test case, print a single integer — the number of good substrings.
4610001131015111116010101
8 5 15 18
Let's define a substring from index $$$l$$$ to index $$$r$$$ as $$$[l, r]$$$.
For the first test case, the good substrings are:
In the second test case, all substrings are good except $$$[2,2]$$$.
In the third test case, all substrings are good.
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